By utilizing multi-antenna technology, spatial modulation based physical layer security approaches can be summarized as precoding, friendly jamming, and transmitting selection[1]}, [2]}, [3]}. In terrestrial networks,
abundant channel uncertainties can be utilized to distinguish with the main and wiretap channels, and recently intelligent reflecting surface (IRS) is introduced to enhance the physical layer security recently[4]}, [5]}. Particularly, secure BF schemes in multiple-input–single-output (MISO) and multiple-input–multiple-output (MIMO) systems are widely investigated [6]}, [7]}, [8]}, and artificial noise (AN) aided secure BF approach is also generally adopted to confuse Eves[9]}, [10]}. In addition, non-orthogonal multiple access (NOMA) based physical layer security approaches have also attracted some attentions[11]}, [12]}.
